Depends on the level of interactivity, an SWF will let you do all the wizz bang, flying in and out etc but is slightly more hassle to have as an offline file to distribute and use. PDFs are the most versatile but but you are limited, you can create hyperlinks to specific pages and text anchors and add forms, video, galleries etc and you are safe in the knowledge that you can email it to anyone and they can open and view it. You can even set it on full screen mode so there are no menus or tools to be visible.
SWF is a deadend. Won’t play on mobile devices or many desktops.
Your assessment of PDF is also incorrect. Unless you can control the reader app, it’s as likely as not that this won’t work. http://boblevine.us/its-okay-to-say-no-to-interactive-pdf/
The best bet for the type of presentation the OP is looking for is Powerpoint! Barring that it could be done as a Fixed Layout EPUB but again, it would be reader dependent.
...used offline by a number of people...
What viewing software can you expect these people to have?
- Many pages should be interactive with objects floating in from different ways.
Interactivity and animation are 2 different things, and the nature of each should be carefully considered with specificity when choosing your platform.
It should be easy to update with more pages and new products.
Easy to update by whom? Only you? Or, others too? This could be the single most important factor in the choice.
To quote your link "My favorite example would be InDesign Magazine. It’s essentially a static publication that has buttons for navigation for next page, previous page and hyperlinks in the TOC. Beyond that the use of interactivity is limited. This is truly a case of less is more and what you should be keeping in mind for your PDF documents."
So for simple interactivity PDF is the best and most versatile, I get your point about the forms and people using 'Preview' on MAC but its a very rare PC that does not have acrobat reader installed, every quote, document, invoice ever produced these days is generated in PDF.
And the workaround for exporting SWF and re-inserting before making the pdf works everytime if you open the PDF in reader.
I think its wrong to write off PDF it is still the simplest and easiest option.
Is the animation truly a must-have requirement? If not, then PDF is a solid choice, IMO. Unless the audience is young kids, you can still design an engaging presentation without movement and simplify the job. A lot of times with presentation design, less is more.
"its a very rare PC that does not have acrobat reader installed, every quote, document, invoice ever produced these days is generated in PDF." Actually, not so rare, and becoming ever less rare because Windows 8, 10, and Macintosh include a PDF viewer. So do Chrome, FireFox and Safari. People find that PDFs just work without downloading software.
Which is fine as long as these PDFs stick to the basic, most simple, interaction. Fancy stuff, forget it. This is a dead end.
Also, more than half of people now use mobile platforms. Consider their experience.